The present invention relates generally to illuminated exit signs and, more particularly, to illuminated exit signs equipped with a plurality of low voltage incandescent lamps.
Under current local fire and building codes, buildings to which the public has access are required to have signage therein identifying the exits. Most of these signs are required to exhibit a specific amount of illumination and, oftentimes, must have an emergency backup power source to provide emergency illumination to the light for a specified period of time during periods when power to the building is discontinued thereby facilitating egress of persons from the building.
Traditionally, two 15-watt incandescent lamps driven by one hundred twenty volt alternating current (120 VAC) have been employed to provide normal illumination while two 3.6-watt incandescent lamps driven by a self contained emergency battery power supply are used for illumination during power failure situations. A switching or transfer device will automatically operate the emergency backup illumination system when a power failure is detected.
While these traditional exit sign lighting arrangements perform adequately, they do have a few drawbacks. Firstly, the relatively high wattage bulbs consume large amounts of electrical energy, particularly, when the building has hundreds of such exit signs. Secondly, the bulbs generate heat and are subject to premature failure due to vibrations and the like requiring a considerable amount of maintenance to change the lamps. Finally, the traditional exit signs, employing the lower wattage lamps during emergency situations, do not provide the same amount of illumination as during normal operation with the larger wattage lamps.
It is an object of the present invention to provide a novel exit sign which uses a plurality low voltage incandescent lamps which consume low amounts of electrical energy and generate only small amounts of heat.
It is also an object to provide such a device having lamps which are not subject to premature failure due to vibrations and the like and therefore require low maintenance.
Still another object is to provide such a device which employs the same lamps during normal operation and emergency operation and thus the same amount of illumination in both situations.
A further object is to provide such an exit light which may be readily and economically fabricated and will enjoy a long life in operation.